I think I'd like to check out some Iron Man comics, but I have no clue where to start. For reference, my knowledge of the character petty much comes from the movies and some scattered bits of Civil War, so I don't have much baseline to work with. My overall Marvel knowledge if very limited also; some X-Men, the movies, that's about it.
Where would you recommend I start? Get the cheap Essential Iron Man volumes? The "Invincible Iron Man" trades? Ultimate? Something else entirely?